Various apparatus are employed for arranging sheet material in a package suitable for use or sale in commerce. One such apparatus, useful for describing the teachings of the present invention, is a mail piece inserter system employed in the fabrication of high volume mail communications, e.g., mass mailings. Such mailpiece inserter systems are typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mail communications where the contents of each mailpiece are directed to a particular addressee. Also, other organizations, such as direct mailers, use mailpiece inserters for producing mass mailings where the contents of each mail piece are substantially identical with respect to each addressee. Examples of inserter systems are the 8 series, 9 series, and APS™ inserter systems available from Pitney Bowes Inc. located in Stamford, Conn., USA.
In many respects, a typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (i.e., a web of paper stock, enclosures, and envelopes) enter the mailpiece inserter as inputs. Various modules or workstations in the mailpiece inserter work cooperatively to process the sheets until a finished mail piece is produced. The precise configuration of each inserter system depends upon the needs of each customer or installation.
Typically, mailpiece inserters prepare mail pieces by arranging preprinted sheets of material into a collation, i.e., the content material of the mail piece, on a transport deck. A typical collation may be created by stacking sheet material on the deck of a sheet accumulator which receives individual sheets from a pre-printed roll or web of sheet material. The roll dispenses a continuous stream of sheet material which is cut to size by a rotating guillotine cutter. Alternatively, pre-cut sheet material which is pre-printed may be stacked in a sheet feeder where a feeding device singulates individual sheets from the stack, i.e., typically the lowermost sheet of the stack.
From the accumulator, the collation of preprinted sheets may continue to a chassis module where additional sheets or inserts may be added to a targeted audience of mail piece recipients. From the chassis module the fully developed collation may continue to a stitcher module where the sheet material may be stitched, stapled or otherwise bound. While the stitched collation may be suitable for insertion directly into a mailpiece envelope, i.e., an envelope which is slightly oversized relative to the stitched collation, it is common for the collation to be folded to reduce the size of the envelope/mailpiece. Common fold arrangements include: bi-fold, tri-fold, Z-fold and gate fold configurations.
The bound/folded collation may then placed into a mailpiece envelope and conveyed to yet other stations for further processing. That is, collation may be inserted into an envelope, closed, sealed, weighed, printed, sorted and stacked. Alternatively, the folded collation may be closed by a tabbing device which places an adhesive tab around the free edges of the collation. Such tabbing devices eliminate the requirement for a mailpiece envelope inasmuch as the folded/tabbed collation is suitably bound for delivery. Additionally, a mailpiece inserter may include a module, i.e., a postage meter, for applying postage indicia based upon the weight and/or size of the mail piece.
While the principal measure of inserter performance is the number of mailpieces produced per unit time, i.e., the throughput of the inserter, a mailpiece inserter must also produce aesthetically pleasing mailpieces. With respect to the aesthetic appeal of a mailpiece, it will be appreciated that the appearance and condition of a mailpiece may be the first, and only, opportunity to offer/present a product or service to a prospective customer/client. A mailpiece having content material which is poorly fabricated, i.e., a collation which is misaligned, skewed or shingled, may inadvertently communicate a message that the product or service being advertised is, similarly, poor/low quality. Conversely, a high quality mailpiece, i.e., one having sharp lines with aligned edges, may communicate a message that the product being offered has a similar level of quality. Upon receipt of such mailpiece, a prospective customer/client may subconsciously think “a company which puts such thought/effort into its mailpiece must produce a high quality product/offer top-notch service”.
While contemporary mailpiece inserters, such as the Flowmaster® Inserter produced by Pitney Bowes Inc. located in Stamford, Conn., produce high quality mailpieces, multi-sheet collations, i.e., having a thickness greater than about ten sheets, can present difficulties, especially when stitched/bound and folded. More specifically, as the thickness of a collation increases, it will be appreciated that folding about a fold line can result in skewing wherein the edges thereof are stepped/staggered.
FIGS. 1a-1c schematically depict a typical folding apparatus 300 (FIG. 1a), and enlarged views of the relevant details of folded multi-sheet collations 310a, 310b (FIGS. 1b and 1c). In FIG. 1, a collation 310 of sheet material is received by the folding apparatus 300 from an upstream stitcher (not shown) where the collation 310 is bound by staples 315 at a centerline CL of the collation 310 and passed upwardly along an inclined tray 320 of the folding apparatus 300 by a pair of nip rollers, i.e., first and second nip rollers 340, 350. As the collation 310 is driven up the tray 320, the leading edge LE of the collation 310 contacts a stop or abutment surface 354 disposed at the uppermost end of the tray 320. Upon engaging the abutment surface 354, the collation 310 bends downwardly along its centerline CL, i.e., towards a fold nip 356, defined by and between a third roller 360 and the first roller 340. As the nip rollers 340, 350 continue to drive the trailing edge TE of the collation 310, the collation 310 is captured by the fold nip 356 to fold the collation 300 along the centerline CL.
By examining FIGS. 1b and 1c, it will be appreciated at least one of the edges forms a stepped/staggered configuration as a result of folding the multi-sheet collation about a fold axis FA. In the context used herein, the term “fold axis” is defined as the virtual axis about which the innermost sheet 300 folds upon itself. It will be appreciated that sheets 301-307 are disposed radially outboard of the fold axis FA and fold around the fold axis FA. Furthermore, sheets 301-307 which are progressively farther outboard of the axis FA, i.e., along arrow R, result in the trailing edge TE of the collation 310 being stepped/staggered so as to define a slope or inclined plane MX1, MX2a, MX2b. Depending upon the location of the staple 315 and the alignment of the leading edge prior to binding, the collation 310 may develop a long shallow slope MX1, along the trailing edge TE (as shown in FIG. 1b) or sloped edges MX2a, MX2b along both leading and trailing edges LE, TE of the collation 310 (as shown in FIG. 1c).
While the lack of edge registration can typically be tolerated for thin collations, e.g., collations having two (2) or three (3) sheets, such poor edge registration is more problematic for larger, thicker collations, e.g., collations having seven (7) or more sheets. That is, as collations increase in thickness, the fold exacerbates the misalignment. If a “cleaner”, more exacting, folded collation is required, then subsequent trimming/cutting operations are required to align the edges, i.e., effect a perpendicular alignment of the collective edges. It will be appreciated, however, that such additional trimming operations introduce additional registration and cutting apparatus which are costly to implement and maintain.
A need, therefore, exists for an apparatus for preparing collations suitable for folding operations. The apparatus prepares collations for folding without the requirement for additional trimming operations and performs multiple operations within a minimal space envelope.